Patch "svcrdma: Skip put_page() when send_reply() fails" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

svcrdma: Skip put_page() when send_reply() fails

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
svcrdma-skip-put_page-when-send_reply-fails.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Chuck Lever <[email protected]>
Date: Tue, 13 Sep 2016 10:52:59 -0400
Subject: svcrdma: Skip put_page() when send_reply() fails

From: Chuck Lever <[email protected]>

commit 9995237bba702281e0e8e677edd5bb225f4f6c30 upstream.

Message from syslogd@klimt at Aug 18 17:00:37 ...
kernel:page:ffffea0020639b00 count:0 mapcount:0 mapping: (null) index:0x0

Aug 18 17:00:37 klimt kernel: flags: 0x2fffff80000000()
Aug 18 17:00:37 klimt kernel: page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)

Aug 18 17:00:37 klimt kernel: kernel BUG at /home/cel/src/linux/linux-2.6/include/linux/mm.h:445!
Aug 18 17:00:37 klimt kernel: RIP: 0010:[<ffffffffa05c21c1>] svc_rdma_sendto+0x641/0x820 [rpcrdma]

send_reply() assigns its page argument as the first page of ctxt. On error, send_reply() already invokes svc_rdma_put_context(ctxt, 1); which does a put_page() on that very page. No need to do that again as svc_rdma_sendto exits.

---
 net/sunrpc/xprtrdma/svc_rdma_sendto.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -635,7 +635,7 @@ int svc_rdma_sendto(struct svc_rqst *rqs
 	ret = send_reply(rdma, rqstp, res_page, rdma_resp, vec,
 			 inline_bytes);
 	if (ret < 0)
-		goto err1;
+		goto err0;
 
 	svc_rdma_put_req_map(rdma, vec);
 	dprintk("svcrdma: send_reply returns %d\n", ret);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/svcrdma-skip-put_page-when-send_reply-fails.patch queue-4.8/xprtrdma-use-complete-instead-complete_all.patch queue-4.8/svcrdma-tail-iovec-leaves-an-orphaned-dma-mapping.patch queue-4.8/xprtrdma-fix-dmar-failure-in-frwr_op_map-after-reconnect.patch